#include<stdio.h>

int Findnum(int ar[], int n)
{
	int i, j;
	for (i = 0; i < n; ++i)
	{
		for (j = 0; j < n; ++j)
		{
			if (i == j)
				continue;
			if (ar[i] == ar[j])
				break;
		}
		if (j == n)
			break;
	}
	return ar[i];
}

void main()
{
	int ar[5] = { 1, 2, 3, 3, 1 };
	int n = sizeof(ar) / sizeof(ar[0]);
	int res = Findnum(ar, n);
	printf("res = %d\n", res);
}